Comparison of reversal activity and mechanism of action of UHRA, andexanet, and PER977 on heparin and oral FXa inhibitors
Comparison of reversal activity and mechanism of action of UHRA, andexanet, and PER977 on heparin and oral FXa inhibitors
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DOI：
10.1182/bloodadvances.2016003616
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发表时间：
2018-08-28
期刊：
影响因子：
7.5
通讯作者：
Haynes, Charles
中科院分区：
文献类型：
--
作者：
Kalathottukaren, Manu T.;Creagh, A. Louise;Haynes, Charles
抗凝剂如普通肝素（UFH）、低分子量肝素（LMWH）、磺达肝素和靶向凝血酶（Ha）或因子Xa（FXa）的直接口服抗凝剂（DOAC）广泛用于预防和治疗血栓栓塞性疾病。然而，抗凝剂相关出血是一个需要监测和中和的问题。UFH解毒剂鱼精蛋白具有局限性，而某些直接FXa抑制剂没有解毒剂。正在开发的改良解毒剂包括用于所有肝素抗凝剂的UHRA（通用肝素抗凝剂）; andexanet alfa（andexanet），一种用于直接FXa抑制剂和LMWH的重组解毒剂;以及cirapartag（PER 977），一种用于UFH、LMWH和某些DOAC的小分子解毒剂。尚未比较这些解毒剂与其假定抗凝剂靶点的结合亲和力。在这里，等温滴定量热法（ITC）被用来确定其推定的目标，每种解毒剂的亲和力。使用凝血和显色FXa测定来表征中和活性，并使用电子显微镜观察在不存在或存在抗凝剂的情况下每种解毒剂对凝块形态的影响。ITC证实了UHRA与所有肝素的结合，andexanet与依度沙班和利伐沙班以及抗凝血酶-依诺肝素复合物的结合。发现PER 977微弱地结合肝素，但不结合所研究的直接FXa抑制剂。对于UHRA和andexanet，发现处于或低于微摩尔水平的亲和力与中和活性相关，而对于PER 977/抗凝剂系统没有观察到逆转活性。发现凝块结构的标准度量与PER 977的活性弱相关。这是第一项比较发育中3种解毒剂的研究，每种解毒剂都通过不同的机制发挥作用。
Anticoagulants such as unfractionated heparin (UFH), low-molecular-weight heparins (LMWHs), fondaparinux, and direct oral anticoagulants (DOACs) targeting thrombin (Ha) or factor Xa (FXa) are widely used in prevention and treatment of thromboembolic disorders. However, anticoagulant-associated bleeding is a concern that demands monitoring and neutralization. Protamine, the UFH antidote, has limitations, while there is no antidote available for certain direct FXa inhibitors. Improved antidotes in development include UHRA (Universal Heparin Reversal Agent) for all heparin anticoagulants; andexanet alfa (andexanet), a recombinant antidote for both direct FXa inhibitors and LMWHs; and ciraparantag (PER977), a small-molecule antidote for UFH, LMWHs, and certain DOACs. The binding affinities of these antidotes for their presumed anticoagulant targets have not been compared. Here, isothermal titration calorimetry (ITC) was used to determine the affinity of each antidote for its putative targets. Clotting and chromogenic FXa assays were used to characterize neutralization activity, and electron microscopy was used to visualize the effect of each antidote on clot morphology in the absence or presence of anticoagulant. ITC confirmed binding of UHRA to all heparins, and binding of andexanet to edoxaban and rivaroxaban, and to the antithrombin-enoxaparin complex. PER977 was found to bind heparins weakly, but not the direct FXa inhibitors studied. For UHRA and andexanet, an affinity at or below the micromolar level was found to correlate with neutralization activity, while no reversal activity was observed for the PER977/anticoagulant systems. Standard metrics of clot structure were found to correlate weakly with PER977's activity. This is the first study comparing 3 antidotes in development, with each exerting activity through a distinct mechanism.